New South Wales Waratahs coach Michael Cheika has slammed the performance of Argentine referee Francisco Pastrana during the Super Rugby round 11 match against the Bulls, saying he was "very disappointed with the officiating, the communication, the language, the ability to decipher and the correct decisions … I'm really disappointed with it; it's cost my team tonight, I think".

The Waratahs led the Bulls 19-15 with 15 minutes to play at Loftus Versfeld in Pretoria, but the hosts scored tries from replacement half-back Francois Hougaard and Man of the Match Morne Steyn to secure a 30-19 verdict.

Cheika ensured he clarified that he was not saying Pastrana's decisions, and those of the assistants, had cost the Waratahs the game even though Bulls fly-half Steyn had kicked 18 points in penalties alone. But he did say the decisions had cost the Waratahs momentum.

"We made plenty of mistakes as well, mind you, but even with all those mistakes we were still dominating the attack side of the game," Cheika said. "We take responsibility for the mistakes we made causing us to lose the game; we could have got the bonus point by making the tackle at the end on the guy coming back. But we wouldn't have been in that position if the previous penalty wasn't given when the guy was lying on the ground, stealing the ball.''

Bulls captain Pierre Spies had no issue with Pastrana's decisions, saying ''I think some calls might have been questioned both ways but I think it was consistent". Spies said: ''I felt the referee was easy to speak to and easy to listen to, and he was clear in his descriptions. When the result goes your way you're always happy, and we're happy with the win.''

Waratahs hooker Tatafu Polota-Nau, meanwhile, said the New South Wales players were to blame for the defeat as they had departed in the closing stages of the match from the game plan that had seen them lead the Bulls with 15 minutes to play.

"What we needed to do was keep believing in our structures," he said. "We did that against the Chiefs at home the previous week, but we went away from that against the Bulls in the last five minutes. It shouldn't be an excuse being away from home and not doing it, but in the heat of the moment we just weren't good enough. There were some communication issues at the end. It is a valuable lesson for the squad, and especially the younger guys who might get the opportunity to come in Pretoria again."

The Waratahs scored three tries to two but couldn't hold off a late charge from the Bulls (video available in Australia only)